Oscar Piastri had to wait, and wait, and wait some more. Then he made his move.

Piastri beat his McLaren teammate and main title rival Lando Norris to win Formula 1's Belgian Grand Prix on Sunday, after heavy rain delayed the start.

Piastri powered past Norris on the first racing lap after the safety car pulled into the pits on lap four, following a delay of more than an hour.

"I knew I was going to try and lift (off the accelerator) a little bit less than Lando did, and try to make it stick," said Piastri, admitting his car felt "lively" as he took on the extra risk through the steeply uphill Eau Rouge corner.

Norris suggested over the radio he was having issues with the battery providing his electric power. McLaren chief executive Zak Brown told broadcaster Sky Sports that there was "a small battery issue which we've got to look at."

Norris cut into Piastri's lead toward the end of the race, but the Australian held on with worn tires, and his British teammate couldn't get close enough to challenge.

Charles Leclerc was third for Ferrari after keeping Red Bull's four-time reigning world champion Max Verstappen behind him all race.

Piastri extended his championship lead over Norris from nine points to 16, and denied his cohort a third Grand Prix win in a row.

The overall leader in this season's standings held off the Briton for a second straight day, having taken second place ahead of his partner in Saturday's sprint, won by Verstappen.

With the exception of the weather, Piastri's overtake of Norris was almost a carbon copy of Verstappen's opening-lap pass against the Australian from second on the grid in the sprint.

Piastri had been disappointed to qualify second for the Grand Prix behind Norris, but it "turns out starting second at Spa is not so bad after all," he said.

Piastri claimed his sixth victory of the season, becoming the first McLaren driver to win the Belgian Grand Prix since Jenson Button in 2012.

In Red Bull's first Grand Prix since firing Christian Horner as team principal, Verstappen failed on an attempt to push past Leclerc at the start, and spent the rest of the race behind the Ferrari driver on the way to fourth place.

George Russell came in fifth for Mercedes following an early pass against Alex Albon, who finished sixth for Williams after holding off Ferrari's Lewis Hamilton, who crossed the line seventh.

Hamilton, the seven-time former world champion, started 18th before carving his way through the field on the wet track early on, but then lost momentum. Liam Lawson took eighth for Racing Bulls, with Gabriel Bortoleto ninth for Sauber, and Pierre Gasly 10th for Alpine.